The preferred embodiment relates to an operative arm of an earth moving machine, and in particular to an operative arm of an excavator, whereto the following disclosure explicitly refers without thereby losing its general nature.
In general, the operative arm of excavators comprises a terminal arm (commonly known as a “dipper stick”) which, at its end, bears a hinged bucket and which is provided with a hydraulic actuator, whose rod is coupled to the bucket via a lever.
As is well known, the bucket can be used both to dig, break up the soil and load and transport material. Operators want high digging or impacting forces on the soil for digging operations, while during loading and transporting operations operators want an opposite need—having a wide angular excursion of the bucket.
Known systems attempting to increase the rotating torque of the bucket (and hence the digging force) include hydraulic systems that provide a momentary increase in pressure during the operation of the actuator that sets the bucket in rotation. However, repeated and frequent pressure peaks entail a high risk of breakage in the hydraulic system of the excavator.